Daily rhythms of body temperature in Acomys russatus: the response to chemical signals released by Acomys cahirinus.

Two species of spiny mice of the genus Acomys--the golden spiny A. russatus and the common spiny A. cahirinus--are sympatric in the arid and hot parts of the Rift Valley in Israel.

Comparative thermoregulatory adaptations of field mice of the genus Apodemus to habitat challenges.

Thermoregulatory abilities, which may play a role in physiological adaptations, were compared between two field mouse species (Apodemus mystacinus and A. hermonensis) from Mount Hermon. While A.

Daily rhythms of metabolic rate and body temperature of two murids from extremely different habitats.

Daily circadian rhythms of body temperature (Tb) and oxygen consumption (VO2) were measured in two murid species, which occupy extremely different habitats in Israel. The golden spiny mouse (Acomys russatus) is a diurnal murid distributed in arid and hot parts of the great Syrio-African Rift Valley, while the broad-toothed field mouse (Apodemus mystacinus) is a nocturnal species that inhabits the Mediterranean woodlands. In both species, the daily rhythms of Tb and VO2 are entrained by the photoperiod.

Burrowing and huddling in newborn porcupine: the effect on thermoregulation.

The newborn cape porcupine Hystrix africaeaustralis is a precocial rodent. However, the newborn spends its first 9 weeks in the burrow. Heat production (oxygen consumption--VO2) and body temperature (Tb) were measured at various ambient temperatures (Ta) in newborn (4-8-week-old) porcupines, with a body mass between 1340-1993 g during summer, from the colony kept at the Mammal Research Institute, University of Pretoria.

Urinary characteristics of the Cape porcupine Hystrix africaeaustralis: effects of photoperiod and temperature.

The Cape porcupine Hystrix africaeaustralis is a large (11-18 kg), nocturnal, burrowing and group-living rodent. It experiences a metabolic response to seasonal acclimatization and is a hind gut fermenter. Changes in the urinary electrolyte and free urinary catecholamine concentrations of Cape porcupines were related to combined changes of ambient temperature and photoperiod regime.

The relative importance of photoperiod and temperature as cues for seasonal acclimation of thermoregulation in pouched mice (Saccostomus campestris: Cricetidae) from southern Africa.

The effect of short photoperiod and cold on metabolism and thermoregulation was investigated in pouched mice (Saccostomus campestris: Cricetidae) from three localities in southern Africa which experience contrasting climatic conditions. Mice were initially acclimated to long photoperiod (14L: 10D) at 25 degrees C, followed first by a decline in photoperiod (to 10L: 14D) and then by a fall in temperature (to 10 degrees C). Minimum observed metabolic rate (identical to basal metabolic rate) was unaffected by the decline in photoperiod but increased significantly following cold acclimation.

Behavior patterns of cold-resistant golden spiny mouse Acomys russatus.

Nesting behavior and food storage were studied in a cold-resistant (CR) population of the golden spiny mouse, Acomys russatus, in Southern Sinai at an altitude of 1600 m. CR-mice, in contrast to cold-sensitive (CS) ones, built nests in which they stored food. Such mice were found to be winter-solitary.

Metabolic rates, food consumption and thermoregulation in seasonal acclimatization of the Cape porcupine Hystrix africaeaustralis.

Metabolic rates by means of oxygen consumption (VO(2)) at various ambient temperatures (T (a)) and food consumption as well as water intake and thermoregulation were compared between individuals of the Cape porcupine Hystrix africaeaustralis acclimated to T (a)=32°C with a photoperiod of 16L:8D summer-acclimated and T (a)=10°C; 8L:16D winter-acclimated. The lower critical temperature as well as overall minimal thermal conductance were lower for the winter-acclimated porcupines when compared to summer-acclimated ones, while VO(2) at the thermoneutral-zone was significantly (P<0.001) higher in the winter-acclimated porcupines.

Rapid development of metastases from basal cell carcinoma presenting as cranial nerve palsies.

A case is reported of metastatic basal cell carcinoma presenting with multiple neurologic deficits 20 months after excision of the primary lesion with good local control. Many features associated with the development of metastasis from basal cell carcinoma were not present in this case.

Thermoregulatory circadian rhythms in the pouched mouse (Saccostomus campestris).

1. Circadian rhythms of body temperature (Tb), oxygen consumption (VO2), and minimal thermal conductance (C) were studied in the pouched mouse, Saccostomus campestris under natural photoperiod during February at a constant ambient temperature of 28 degrees C. 2.

Urine analysis of European moles Talpa europaea and white rats Rattus norvegicus kept on a carnivore's diet.

1. The urine compositions of the European mole Talpa europaea and of the white rat Rattus norvegicus (albino) kept on a carnivore's diet were compared. 2.

Enzymatic activity in crude oil contaminated rats.

The activity of enzymes found in the plasma, malate dehydrogenase (MDH) and lactate dehydrogenase (LDH), and enzymes from erythrocytes, glucose-6-phosphate dehydrogenase (G-6-PDH) and catalase, was studied in rats contaminated by crude oil. Crude oil (tube fed) contamination caused a significant increase in MDH and LDH activity 96 hr after contamination while a decrease in activity was noted in 6-6-PDH and catalase. An additional contamination (1 week after the first contamination), measured 96 hr after contamination, caused a relative decrease in MDH and LDH activity while there was a contrasting relative increase in G-6-PDH and catalase activity.

Geographical variations in heat production and dissipation within two populations of Rhabdomys pumilio (Muridae).

A comparative study of heat production and dissipation was carried out on Rhabdomys pumilio from two extremely different climatic zones. Our results show higher oxygen consumption (Vo2) values for the desert population at Ta = 5 degrees C when compared to the mesic population. The overall thermal conductance is also higher for the desert population.

The ecophysiological significance of calcium bicarbonate in the urine of subterranean rodents: testing a hypothesis.

1. A comparative study of calcium and bicarbonate in the urine was carried out on the subterranean mole rat Cryptomys hottenttus and the terrestrial vlei rat Otomys irroratus. 2.

Urine analysis of three rodent species with emphasis on calcium and magnesium bicarbonate.

The urine composition of three rodent species, mole rat Spalax ehrenbergi, the golden hamster Mesocricetus auratus and the white rat Rattus norvegicus was studied. These three species represent different degrees of fossoriality. The results show that the urine of the species that show a higher degree of fossoriality, the mole rat and the hamster, contain high values of calcium and magnesium bicarbonates when compared with the white rat.

Adaptive variations in heat production within Gerbils (genus Gerbillus) from different habitats.

Species of the genus Gerbillus are very common among the rodent fauna inhabiting arid zones and dune habitats in the palaearctic region. In Israel G. nanus is distributed in extreme arid areas, while G.

Photoperiodic effects on thermoregulation in a 'blind' subterranean mammal.

Thermoregulatory responses to changes in photoperiod were studied in the 'blind' mole rat Spalax ehrenbergi (Nehring). Acclimation of cold-sensitive individuals to short photoperiod (8L:16D) at an ambient temperature (Ta) of 22 degrees C increased their thermoregulatory capacity in cold conditions, when compared to individuals which were acclimated to a photoperiod of 12L:12D at the same Ta. Acclimation of cold-resistant individuals to Ta = 17 degrees C but with a photoperiod of 16L:8D caused a decrease in thermoregulatory capacity.

Long scotophase acclimation increases free urinary catecholamine content in the rat.

1. Acclimation of laboratory rats Rattus norvegicus albino to long scotophase 8L:16D and 4L:20D at an ambient temperature (Ta) of 25 degrees C caused an increase in urinary free catecholamine compared to 12L:12D at Ta = 25 degrees C. 2.

Effects of melatonin on heat production and enzymatic activity in diurnal and in nocturnal rodents.

1. Heat production by means of oxygen consumption (Vo2), and enzymatic activity of malate dehydrogenase (MDH), lactate dehydrogenase (LDH), and glucose-6-phosphate dehydrogenase (G6PDH) were studied in diurnal (Rhabdomys pumilio) as well as nocturnal (Praomys natalensis) murids, as a response to melatonin treatment. 2.

Non shivering thermogenesis and implication of the thyroid in cold labile and cold resistant populations of the golden spiny mouse (Acomys russatus).

The golden spiny mouse is dependent on non shivering thermogenesis (N.S.T.